"Stimpy" wrote in message
...

With the fragmentation of the rail industry it's now cheaper than
transporting them by rail in many cases

Not really anything to do with the fragmentation of the industry. It's been
happening since BR days. With increased service frequency and faster
services it simply isn't possible to path movements of shunting locomotives
or defective (speed-restricted) main-line locomotives and/or stock between
scheduled services. There isn't the time for them to get from one passing
loop to another without causing chaos to the timetabled service. Therefore
it is far more logical to send them on the back of a lorry.